Background:
Vector-borne diseases are quite prevalent globally and are one of the major
causes of deaths due to infectious diseases. There is an availability of synthetic insecticides, however,
their excessive and indiscriminate use have resulted in the emergence of resistant varieties of insects.
Thus, a search for novel biopesticide has become inevitable.
Methods:
Rotenoids were isolated and identified from different parts of Medicago sativa L. This group
of metabolites was also identified in the callus culture, and the rotenoid content was monitored during
subculturing for a period of 10 months. Enhancement of the rotenoid content was evaluated by feeding
precursors in a tissue culture medium.
Results:
Four rotenoids (elliptone, deguelin, rotenone and Dehydrorotenone) were identified, which
were confirmed using spectral and chromatographic techniques. The maximum rotenoid content was
found in the seeds (0.33±0.01%), followed by roots (0.31±0.01%) and minimum in the aerial parts
(0.20±0.05%). A gradual decrease in the rotenoid content was observed with the ageing of subcultured
tissue maintained for 10 months. The production of rotenoids was enhanced up to 2 folds in the callus
culture using amino acids, Phenylalanine and Methionine as precursors as compared to the control. The
LC50 value of the rotenoids was found to be 91 ppm and 162 ppm against disease vectors of malaria and
Dracunculiasis, respectively.
Conclusion:
The study projects M. sativa as a novel source of biopesticide against the disease vectors of
malaria and Dracunculiasis. The use of precursors to enhance the rotenoid content in vitro can be an
effective venture from a commercial point of view.
